The present invention relates to a power output improvement apparatus for an internal combustion engine and in particular to a valve timing system for an internal combustion engine, which is also applicable to engines having multi-inlet and multi-exhaust configurations per combustion chamber.
Many systems have been developed to increase the power output of internal combustion engines. Some of these utilise multiple valves, and variable valve timing such as BMW""s patented Vanos variable valve timing system.
The present invention provides a variable valve timing system comprising:
a cam follower adapted to move the valve between its closed and open position, said follower having a contoured engagement surface;
a cam, located on and driven by a cam shaft, and having a contact surface adapted to engage the engagement surface of the cam follower and move the cam follower to operate the valve, the contact surface of the cam being contoured at least along a portion thereof; and
rotational means to rotate the cam follower relative to the plane of movement of the cam such that the contoured contact surface of the cam and contoured engagement surface of the cam follower engage each other earlier and disengage later than if the cam follower is not rotated.